A model to describe the spontaneous formation of military and economic coalitions among a group of countries is proposed using an extended version of spin glass theory. Between each couple of countries, there exists a bond exchange coupling which is either zero, cooperative or conflicting. It depends on their common history, specific nature, and cannot be varied. Then, given a frozen random bond distribution, coalitions are found to spontaneously form. However they are also unstable making the system very disordered. Countries shift coalitions all the time. Only the setting of macro extra national coalition are shown to stabilize alliances among countries. The model gives new light on the instabilities, which occurred in Eastern Europe after the Warsaw pact dissolution in contrast to the previous communist stability. Current European stability is also discussed with respect to the European Union internal tensions produced by uncontrolled national public debts.

Article lié / related article : http://link.springer.com/article/10.1140%2Fepjb%2Fe2014-50264-4